Abstract: In this paper we have made a concise survey on various privacy preserving techniques in cloud. Homomorphic Authenticable Ring Signature (HARS), privacy-preserving public auditing System for data storage security are discussed. Public key cryptosystem, the MD5 Message-Digest Algorithm are depicted. Proof-Of-Retrievability system for public verifiability is described. Dynamic Provable Data Possession (DPDP) to enlarge the PDP model is discussed in detail. LT codes based cloud storage service (LTCS) to empower efficient decoding, Merkle Hash Tree (MHT) for the block tag Authentication is discussed.

Keywords: Privacy Preserving, Public Auditing, DPDP, PDP, Cloud Computing.